US5183873AExpiredUtility

Room temperature stable organopolysiloxane compositions

57
Assignee: WACKER SILICONES CORPPriority: Oct 21, 1991Filed: Oct 21, 1991Granted: Feb 2, 1993
Est. expiryOct 21, 2011(expired)· nominal 20-yr term from priority
Inventors:George J. Viksne
C08K 5/098C08G 77/12Y10S528/901C08L 83/04C08G 77/16
57
PatentIndex Score
12
Cited by
4
References
16
Claims

Abstract

Compositions which are stable at room temperature, but when heated to an elevated temperature crosslink to form elastomeric solids comprising (A) organopolysiloxanes containing silicon bonded hydroxyl groups, (B) a crosslinking agent selected from (a) silanes, (b) partial hydrolyzates thereof and (c) organohydrogenpolysiloxanes and (C) an aluminum salt of a carboxylic acid which is a solid at room temperature. When the compositions are heated to a temperature of at least 50° C. and more preferably from 100° to 350° C., they cure to form elastomeric solids.

Claims

exact text as granted — not AI-modified
What is claimed is: 
     
       1. A composition which is stable at room temperature, but when heated to an elevated temperature cures to an elastomeric solid which comprises (A) an organopolysiloxane having silicon bonded hydroxyl groups, (B) a crosslinking agent selected from the group consisting of (a) a silane of the formula   R.sub.m Si(Z).sub.4-m,       (b) partial hydrolyzates of silane (a) and   (c) an organohydrogenpolysiloxane of the average unit formula   R.sub.n HSiO.sub.3-n     where R is selected from the group consisting of a monovalent hydrocarbon radical having from 1 to 18 carbon atoms and a substituted monovalent hydrocarbon radical having from 1 to 18 carbon atoms, Z is selected from the group consisting of a hydrocarbonoxy group of the formula (--OR') and a hydrocarbonoxy-hydrocarbonoxy group of the formula (--OR"OR'), where R' is a monovalent hydrocarbon radical having from 1 to 10 carbon atoms, R" is a divalent hydrocarbon radical having from 2 to 10 carbon atoms, m is an integer of from 0 to less than 2 and n is an integer greater than 0, but less than 2 and (C) an aluminum salt of a carboxylic acid having from 8 to 18 carbon atoms which is solid at room temperature.     
     
     
       2. The composition of claim 1, wherein the organopolysiloxane (A) is represented by the formula   HO(SiR.sub.2 O).sub.x H     where R is selected from the group consisting of a monovalent hydrocarbon radical having from 1 to 18 carbon atoms and a substituted monovalent hydrocarbon radical having from 1 to 18 carbon atoms and x has a value of at least 2.   
     
     
       3. The composition of claim 1, wherein the organohydrogenpolysiloxane has a viscosity of from about 10 to 1000 mPa·s at 25° C. 
     
     
       4. The composition of claim 1, wherein the crosslinking agent (B) is selected from the group consisting of (a) a silane of the formula   R.sub.m Si(Z).sub.4-m     where R is selected from the group consisting of a monovalent hydrocarbon radical having from 1 to 18 carbon atoms and a substituted monovalent hydrocarbon radical having from 1 to 18 carbon atoms, Z is selected from the group consisting of a hydrocarbonoxy group of the formula (--OR') and a hydrocarbonoxy-hydrocarbonoxy group of the formula (--OR"OR'), where R' is a monovalent hydrocarbon radical having from 1 to 10 carbon atoms and R" is a divalent hydrocarbon radical having from 1 to 10 carbon atoms and m is an integer of from 0 to less than 2 and (b) a partial hydrolyzate of said silane having up to 10 silicon atoms.   
     
     
       5. The composition of claim 1, wherein the composition also contains an organic peroxide. 
     
     
       6. The composition of claim 4, wherein the composition also contains an organic peroxide. 
     
     
       7. The composition of claim 1, wherein the crosslinking agent (B) is an organohydrogenpolysiloxane (c) of the average unit formula   R.sub.n HSiO.sub.3-n     where R is selected from the group consisting of a monovalent hydrocarbon radical having from 1 to 18 carbon atoms and a substituted monovalent hydrocarbon radical having from 1 to 18 carbon atoms and n is an intger greater than 0, but less than 2.   
     
     
       8. The composition of claim 1, wherein the organohydrogenpolysiloxane has a viscosity of from, 10 to 1000 mPa·s at 25° C. 
     
     
       9. The composition of claim 7, wherein the aluminum salt of a carboxylic acid is aluminum octoate. 
     
     
       10. The composition of claim 1, wherein the organopolysiloxane (A) is a mixture containing an organopolysiloxane having silicon bonded hydroxyl groups and a silicone resin containing from 0.1 to 10 percent by weight of hydroxyl groups. 
     
     
       11. A process for preparing a composition which is stable at room temperature, but when heated to an elevated temperature cures to elastomeric solid which comprises mixing (A) an organopolysiloxane having silicon bonded hydroxyl groups with (B) a crosslinking agent selected from the group consisting of (a) a silane of the formula   R.sub.m Si(Z).sub.4-m,       (b) partial hydrolyzates of silane (a) and   (c) an organohydrogenpolysiloxane of the average unit formula   R.sub.n HSiO.sub.3-n     where R is selected from the group consisting of a monovalent hydrocarbon radical having from 1 to 18 carbon atoms and a substituted monovalent hydrocarbon radical having from 1 to 18 carbon atoms, Z is selected from the group consisting of a hydrocarbonoxy group of the formula (--OR') and a hydrocarbonoxy-hydrocarbonoxy group of the formula (--OR"OR'), where R' is a monovalent hydrocarbon radical having from 1 to 10 carbon atoms, R" is a divalent hydrocarbon radical having from 2 to 10 carbon atoms, m is an integer of from 0 to less than 2 and n is an integer greater than 0, but less than 2 and (C) an aluminum salt of a carboxylic acid having from 8 to 18 carbon atoms which is solid at room temperature.     
     
     
       12. The process of claim 11, wherein the crosslinking agent (B) is selected from the group consisting of (a) a silane of the formula   R.sub.m Si(Z).sub.4-m     where R is selected from the group consisting of a monovalent hydrocarbon radical having from 1 to 18 carbon atoms and a substituted monovalent hydrocarbon radical having from 1 to 18 carbon atoms, Z is selected from the group consisting of a hydrocarbonoxy group of the formula (--OR') and a hydrocarbonoxy-hydrocarbonoxy group of the formula (--OR"OR'), where R' is a monovalent hydrocarbon radical having from 1 to 10 carbon atoms and R" is a divalent hydrocarbon radical having from 1 to 10 carbon atoms and m is an integer of from 0 to less than 2 and (b) a partial hydrolyzate of said silane having up to 10 silicon atoms.   
     
     
       13. The process of claim 11, wherein the crosslinking agent (B) is an organohydrogenpolysiloxane of the average unit formula   R.sub.n HSiO.sub.3-n     where R is selected from the group consisting of a monovalent hydrocarbon radical having from 1 to 18 carbon atoms and a substituted monovalent hydrocarbon radical having from 1 to 18 carbon atoms and n is an integer greater than 0, but less than 2.   
     
     
       14. The process of claim 12, wherein the organopolysiloxane (A) is represented by the formula   HO(SiR.sub.2 O).sub.x H     where R is selected from the group consisting of a monovalent hydrocarbon radical having from 1 to 18 carbon atoms and a substituted monovalent hydrocarbon radical having from 1 to 18 carbon atoms and x has a value of at least 2.   
     
     
       15. An elastomeric solid which is obtained by heating the composition of claim 1 to a temperature of at least 50° C. 
     
     
       16. A process for preparing an elastomeric solid which comprises heating the composition of claim 1 to a temperature of at least 50° C.

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